Projecton device for projecting an image onto a projection surface, and a projection unit for coupling to a projector

ABSTRACT

A projection arrangement for projecting an image onto a projection surface, said arrangement comprising a light source ( 26 ), a film stage ( 2 ), arranged following said light source, for holding a positive image recorded on a carrier medium, and projection optics ( 3 ) for projecting a illuminated positive image, is provided with a control unit ( 25 ), a light modulator ( 10 ) controllable by said control unit in order to generate an additional image on the basis of predetermined image data, said light modulator being followed by an optical device ( 11 ) for projecting the additional image onto the projection surface ( 34 ), and with a beam splitter ( 6 ) arranged between the light source ( 26 ) and the film stage ( 2 ) so as to split the light from the light source ( 26 ) into a first partial beam directed to the film stage ( 2 ) in order to illuminate the positive image and into a second partial beam which may be directed to the light modulator ( 10 ). Thus, a projection arrangement is provided which allows to project additional images, such as subtitles, in addition to the illuminated positive image.

[0001] The invention relates to a projection arrangement for projectingan image onto a projection surface, said arrangement comprising a lightsource, a film stage, arranged following the light source, for holding apositive image recorded on a carrier medium, and projection optics forprojecting a illuminated positive image. The invention further relatesto a projection unit for coupling to a projector.

[0002] Such a projection arrangement is, for example, a projector forprojecting a motion picture and comprises a light source, a mechanicalfilm stage and projection optics. The light source emits a light raybundle which illuminates positive images on a film guided transverselyto the light propagation direction of the light ray bundle. Theilluminated positive images are projected onto a screen by theprojection optics. During operation, the film is unwound from a filmreel or a film disk on one side of the film stage, guided across saidfilm stage, and wound up on the other side of the film stage on anotherfilm reel or another film disk. The film is guided discontinuouslyacross the film stage such that the film is moved past a picture gate onthe film stage and stopped, 24 times per second, each individual imagebeing illuminated twice. At the same time, the control signals for thetheater sound system are also sampled. Such projector only allowsconventional motion pictures to be projected. A simultaneous projectionof additional images, which are present only as digital and/or analogdata and which, in order to be projected, have to be generated first onthe basis of said data, is not possible.

[0003] Such simultaneous projection of additional images isadvantageous, for example, for the projection of subtitles in aforeign-language movie, because it would then no longer be required toproduce individual copies of the motion picture comprising thecorresponding subtitles for a certain speech area. Accordingly, theoriginal movie could be used with corresponding subtitle filescontaining the data for the subtitles in the individual languages. Forthe projection of such subtitles, which are present only as data,projection devices may be employed which comprise light modulators forimaging, said light modulators allowing to generate the subtitles asadditional images according to said data. As light modulators, forexample, LCD modules or tilting mirror matrices (DMD chips) are used. Ifsuch projection arrangement is provided in addition to the projector forprojecting conventional movies, this will result in a high cost ofacquisition, since an entire projection arrangement needs to beacquired.

[0004] Now, the invention is intended to remedy this and to improve theaforementioned projection arrangement such that the projectionarrangement is suitable for simultaneous projection of a positive imagerecorded on a carrier medium and of an additional image to be generatedon the basis of predetermined image data. Moreover, a projection unitfor coupling to a projector is to be proposed.

[0005] According to the invention, this problem is solved, in theprojection arrangement of the above-mentioned type, by a control unit, alight modulator which is controllable by said control unit in order togenerate an additional image on the basis of predetermined image dataand which is followed by an optical device for projecting the additionalimage onto the projection surface, and a beam splitter arranged betweenthe light source and the film stage, said beam splitter splitting thelight from the light source into a first partial beam directed to thefilm stage for transilluminating the positive image and into a secondpartial beam, which may be directed to the light modulator.

[0006] In an advantageous embodiment of the projection arrangementaccording to the invention, the light incident on the beam splitter hasa predetermined beam cross-section and the beam splitter is formed suchthat the degree of splitting between the first and second partial beamvaries across the beam cross-section. For example, during the projectionof subtitles as additional images, it is thus possible to illuminate thepositive image with light of as great a brightness as possible, while asmall area of the beam cross-section is used to impinge on the lightmodulator.

[0007] In an advantageous embodiment of the projection arrangementaccording to the invention, the beam splitter comprises a partiallyreflective mirror, a beam splitter block, or a deflecting element (e.g.a mirror or a prism) which is arranged partially in a beam cross-sectionof the light ray bundle emitted by the light source. Thus, reliablesplitting of the light ray bundle is achieved.

[0008] Preferably, the projection arrangement according to the inventionmay be further embodied such that the beam splitter is movable into andout of the optical path between the light source and the film stage.There may further be provided a deflecting device which, when the beamsplitter is moved out of the optical path between the light source andthe film stage, is movable into said optical path in order to direct thelight from the light source onto the light modulator. Thus, using thisprojection arrangement, in addition to the simultaneous projection ofthe additional image, this projection arrangement may also be operatedsuch that either a illuminated positive image or an image generated bythe light modulator is projected.

[0009] Preferably, the beam splitter, the light modulator and theoptical device are provided as an attachable projection module. Thisallows the light source of a conventional projector for projectingpositive images to be used also as the light source for the lightmodulator. Further, the conversion of an already existing, conventionalprojector to the projection arrangement according to the invention iseasily possible, because the projection module only needs to be coupledto the conventional projector.

[0010] Particularly advantageously, the projection arrangement accordingto the invention may be further embodied such that a splitting device isprovided which splits the light from the light source into differentcolors, and that the light modulator comprises several light-modulatingunits, each of which modulates one of said colors. This configurationallows to obtain light outputs which meet the brightness requirements ofmovie theaters.

[0011] In a further advantageous embodiment of the projectionarrangement according to the invention, combining optics are providedwhich combine the light emitted by the light-modulating units to formone single light bundle and guide it to the optical device. Thisadvantageously allows the modulated light of different colors to beimaged on the screen by means of an optical device.

[0012] Preferably, the projection arrangement according to the inventionis further embodied such that the light modulator comprises an LCDmodule—which may be in the form of a transmission or reflection module—aGLV module, or a tilting mirror matrix. Thus, a high-quality image maybe generated.

[0013] In a further advantageous embodiment, the projection optics andthe optical device of the projection arrangement according to theinvention are comprised in one single projection device. Thus, it ispossible to provide a projection arrangement requiring only oneprojection device, which saves costs.

[0014] The projection arrangement according to the invention mayadvantageously be embodied such that a memory for storing data isprovided. Said memory may be a digital memory, e.g. a computer harddisk, or may also be an analog memory, such as a conventional videotape. By providing such memory, the entire data for the additionalimages may be stored in the projection arrangement, so that there is noneed for high transmission capacities of a connection with an externalmemory.

[0015] In another advantageous embodiment of the invention, theprojection arrangement according to the invention comprises an interfacefor receiving data. Said interface may be, for example, a DVD drive. Itmay also be an interface for a computer network, such as the internet.This allows easy transmission of the data to the projection arrangement.

[0016] In a further advantageous embodiment of the invention, a displaydevice and an image recording device are provided, said image recordingdevice being able to record the image projected onto the projectionsurface and to represent it on the display device. When the imagerecording device records the film projected onto the projection surfaceand reproduces it on the display device, it is possible to control theperformance from outside the auditorium. Thus, for example, failure ofthe projection lamp or of the auditorium lighting may be diagnosed atonce.

[0017] The projection unit according to the invention for coupling to aprojector, which projector comprises a light source, a film stage,arranged following said light source, for holding a positive imagerecorded on a carrier medium, as well as projection optics forprojecting a illuminated positive image onto a projection surface,comprises a control unit, a light modulator controllable by said controlunit in order to generate an additional image on the basis ofpredetermined image data, an optical device, arranged following thelight modulator, for projecting the additional image onto a projectionsurface, and a beam splitter which, when the projection module iscoupled to the projector, is arranged between the light source and thefilm stage and splits the light from the light source into a firstpartial beam directed to the film stage in order to illuminate thepositive image and into a second partial beam which may be directed tothe light modulator. This projection unit allows easy and fast retrofitof a conventional projector.

[0018] A more detailed description of the invention, compared with amovie projector known from the prior art, shall be given below basicallyby way of example and in view of the drawings, wherein:

[0019]FIG. 1 shows a schematic top view of a projection arrangementaccording to the invention;

[0020]FIG. 2 shows a top view of a light modulator according to anembodiment;

[0021]FIG. 3 shows a block diagram of the projection arrangementaccording to the invention;

[0022]FIG. 4 shows a top view of the light modulator according to afurther embodiment;

[0023]FIG. 5 shows a side view of the light modulator shown in FIG. 4;

[0024]FIGS. 6 and 7 show schematic representations explaining analternative embodiment of a light modulator; and

[0025]FIG. 8 shows a schematic top view of a conventional movieprojector.

[0026] For a better understanding of the projection arrangementaccording to the invention, a brief description shall be given, withreference to FIG. 8, of the basic structure of a conventional projectorfor projecting positive images or positive films. Such conventionalprojector contains a lamp housing 1, a mechanical film stage 2 and aprojection lens 3. In the lamp housing 1, a light source (not shown) isarranged, which emits a light ray bundle 4 transilluminating a positiveimage on a film 5 held on the mechanical film stage 2, which film isguided transversely to the light propagation direction of the light raybundle 4. The illuminated positive image is projected onto a projectionsurface (not shown) by means of the projection lens 3.

[0027]FIG. 1 shows a schematic top view of the projection arrangementaccording to the invention. Like the conventional projector shown inFIG. 8, the projection arrangement comprises a lamp housing 1, wherein alight source (e.g. a xenon lamp), not shown, is arranged, a mechanicalfilm stage 2 and a projection lens 3. In addition, the projectionarrangement according to the invention includes a beam splitter unit 6and an additional-image generating module 7. The beam splitter unit 6comprises a first partially reflective mirror 8, which is arranged inthe optical path between the lamp housing 1 and the mechanical filmstage 2 and which splits the light ray bundle 4 from the light sourceinto a first light ray bundle directed to the film stage 2 and into asecond light ray bundle, which is deflected substantially perpendicularto the light propagation direction from the lamp housing 1 to themechanical film stage 2. The ratio of the light intensities of the firstand second light ray bundles may be 1:1. Other ratios are also possible.The second light ray bundle is incident on a second deflecting mirror 9of the beam splitter unit 6 and is deflected by said second deflectingmirror 9 at approximately 90° such that the light ray bundle deflectedby the second deflecting mirror 9 is preferably propagated parallel tothe light ray bundle 4 exiting from the lamp housing 1. Said deflectedsecond light ray bundle is incident on the additional-image generatingmodule 7.

[0028] As shown in FIG. 2, the additional-image generating module 7comprises a light modulator 10 and projection optics 11. The lightmodulator 10 is controlled on the basis of predetermined image data insuch a manner that it generates an image which consists of image pixels,which image is projected by means of the projection optics 11. Further,there may also be provided a light integrator or a light mixing rod (notshown), which precedes the light modulator 10 and transforms the lightray bundle 4 in such a manner that the light-modulating units 21, 22, 23described below are illuminated as uniformly as possible. The lightmodulator 10 comprises a color-splitting unit 12 having three mirrors13, 14 and 15, which are arranged successively along a first opticalaxis, each of said mirrors being tilted about 45° relative to said firstoptical axis. The mirror 13 disposed on the inlet side is a mirror whichonly reflects the blue component of the white light of the light raybundle. The remaining color components of the light pass through themirror 13 and are incident on the next mirror 14, which only reflectsthe green color component thereof. The red light component passingthrough this mirror 14 is then reflected by the mirror 15, whichselectively reflects red light.

[0029] The light modulator 10 further includes a color-combining unit 16comprising three mirrors 17, 18 and 19. Said mirrors 17, 18 and 19 arearranged along a second optical axis, which is parallel to the firstoptical axis of the light bundle incident on the light modulator 10.Further, these mirrors 17, 18 and 19 are tilted at 45° relative to thesecond optical axis and arranged such that the blue, green and red lightreflected by the mirrors 13, 14 and 15, respectively, is reflected so asto be propagated along the second optical axis. Thus, the blue, greenand red light ray bundles are united to form one common light ray bundle20. Further, the light modulator 10 comprises three light-modulatingunits 21, 22 and 23 (e.g. LCD modules), each modulating one colorcomponent of the light split into blue, green and red color components,thus creating the required individual color pixels whose combinationyields the desired image. In the embodiment shown in FIG. 2, the lightmodulation unit 21 for the blue light component is arranged between themirrors 17 and 18. The light modulation unit 22 for the green lightcomponent is arranged between the mirrors 14 and 18, and the lightmodulation unit 23 for the red light component is arranged between themirrors 14 and 15. The modulation using the light-modulating units 21,22 and 23 is carried out according to the digital and/or analog datapresent. The light ray bundle 20, which is color-modulated, is thenprojected onto the screen (not shown) by means of the projection optics11. The mirrors 13, 14, 15 and 21, 22, 23 may be in the form ofdichroitic mirrors.

[0030]FIG. 3 shows a block diagram of the projection arrangementaccording to the invention. As is evident from FIG. 3, the projectionarrangement according to the invention comprises a projection unit 24and a control unit 25. The projection unit 24 includes the lightmodulator 10, the projection optics 11, the lamp 26 arranged in the lamphousing 1, the beam splitter unit 6, the mechanical film stage 2 and theprojection lens 3. The film 5 is fed to the mechanical film stage 2. Thecontrol unit 25 comprises a data input 27, a monitoring unit 28, a soundoutput 29, a memory 30, an operating unit 31, which includes an inputunit, e.g. a keyboard, and a display device, e.g. a monitor, and furthercomprises an output interface (not shown), by which, e.g., the dimmingof the auditorium lighting or the movement of a curtain away from theprojection surface may be controlled. The control unit 25 may beprovided as a separate unit, which may be set up separately from theprojection unit 24, e.g. in a different room.

[0031] Various data links may be used to transmit the data from thecontrol unit 25 to the projection unit 24. It is essential that thebandwidth be sufficient for data transmission. For example, the LVDSsystem (Low Voltage Differential Signaling System, of the NationalSemiconductor company) or the PanelLink system of the Silicon Imagecompany, which allow transmission of large data volumes via a cablehaving only two wires, are advantageous.

[0032] The data 32 are fed to the control unit 25 via the data input 27.Said data input 27 may be, on the one hand, an interface to an externalnetwork, e.g. the internet. On the other hand, said data input 27 mayalso be realized by a drive receiving a storage medium, such as a DVDdrive. The data entered via the data input 27 may either be written tothe memory 30 by the monitoring unit 28 or used directly to control thelight modulator 10 in the projection unit 24. The monitoring unit 28 mayoptionally filter out sound data from the input data and apply them to atheater sound system 33, synchronously with the image data, via thesound output 29.

[0033] The monitoring unit 28 may further use the image data eitherunmodified to control the light modulator 10, or may perform anadjustment of format or resolution or any other desired graphicaltransformation, said adjustment or transformation being realizable bothby hardware and by software.

[0034] Further, the monitoring unit 28 allows to compensate distortionscaused by the projection optics 11. These may be, for example,pin-cushion or barrel distortions. To this end, the image data forcontrolling the light modulator 10 are pre-distorted by the monitoringunit 28 in such a manner that said pre-distortion is compensated by thedistortion of the projection optics 11, so that an image exhibiting aslittle distortion as possible is projected on the screen 34. If desired,the monitoring unit 28 also allows to perform color adjustments andcolor conversions.

[0035] The above-described data processing operations may be carried outeither during projection or may be performed in advance, with theprocessed data then being stored in the memory 30.

[0036] Advantageously, the projection arrangement according to theinvention may also comprise a camera (not shown), which is installed inthe auditorium and records the image projected onto the screen 34 andtransmits it to the control unit 25, which displays the transmittedimage on the monitor of the operating unit 31. This allows to monitorthat the movie performance is effected correctly and, if necessary, totake action immediately.

[0037] During projection, the image of the conventional motion pictureis usually projected by the transillumination process. In addition, theadditional-image generating module 7 generates and, at the same time,projects additional images, such as subtitles. The optionally requiredsynchronisation between the projection of the movie and of the subtitlesmay be effected, for example, on the basis of the sound signals (opticalsound, or control signals for digital sound included with theconventional movie. Thus, for example, the original sound may also beincluded completely or as excerpts in the subtitles file so as to allowmeasurement of the time difference that may occur under certaincircumstances, by comparing these signals. A compensation of a measureddifference may then be effected, for example, by omitting repetitions ofindividual images of the only slowly varying subtitles.

[0038] The additional-image generating module 7, the beam splitter unit6 and the projection optics 11 may be provided as a projection modulewhich can be coupled to and uncoupled from a conventional projector,such as that shown, for example, in FIG. 8. By being provided as aseparate, portable projection module, this projection module may becoupled, for example, to the projector as required. It is also possibleto acquire such a projection module for several projectors and to couplethe projection module to the desired projector in each case.

[0039] In order to allow easy coupling of the projection module to saidconventional projectors, there is preferably provided a support, whichconsists of a first coupling device provided on the respective projectorand a second coupling device provided on the projection module. Thefirst coupling device is disposed in a defined spatial relationship tothe conventional projector. Preferably, it is attached to the foot ofthe lamp housing 1 of the projector and comprises a base having aself-centering three-point support, onto which the projection module maybe placed. The self-centering three-point support comprises, forexample, three conical sleeves, in which corresponding counterparts ofthe projection module engage when the projection module is restedthereon. Said conical sleeves may be individually adjusted in theirposition perpendicular to the plane of the supporting surface and may beadjusted together in the plane of the supporting surface. Thus, thesupport has an adjustment means, which is provided in the first couplingdevice remaining on the projector so that the projection module merelyneeds to be placed on the three-point support and is then immediatelyready for operation.

[0040] Advantageously, the support may further comprise a data andcurrent interface, which comprises a first plug element provided on thefirst coupling device and a second plug element provided on the secondcoupling device. Said plug elements are arranged such that, when theprojection module is placed on the three-point support, a mechanical andelectrical contact is established. To this end, one of said plugelements may be floatingly mounted, while the other of said plugelements has a fixed position.

[0041] When the support, as described above, is provided with a datainterface, a corresponding supply line is provided for each conventionalprojector. This allows to provide just one single control unit 25 forall of the conventional projectors, so that the projection module andthe control unit 25 are provided as separate units. On the one hand,this increases the transportability of the projection module. On theother hand, the control unit may be arranged at any desired location, sothat there is no interference with the space in the projection booth inwhich the conventional projector is located.

[0042] Alternatively, the projection module may comprise the controlunit 25. In this case, the projection module is an operable,transportable unit.

[0043]FIGS. 4 and 5 show an alternative embodiment of the lightmodulator 10. In this embodiment, three prisms 35, 36 and 37 arearranged and provided such that, in the first prism 35, blue light fromthe light ray bundle deflected by the second deflecting mirror 9 isfiltered out by reflection and directed to a tilting mirror matrix 38.Of the remaining light bundle, only the red light is filtered out byreflection in the second prism 36 and directed to a tilting mirrormatrix 39. The remaining light, namely the green component, is directedto a tilting mirror matrix 40 by a third prism 37. The individual colorcomponents are suitably modulated and reflected back by the tiltingmirror matrices 38, 39 and 40 according to the image data so that theyare combined to form one common light ray bundle 20, which is projectedonto the screen via the projection optics 11. FIG. 5 schematically showsthat the individual mirrors may be tilted such that the imaging light isreflected back to the projection optics (solid line) or reflected backonto a diaphragm element 41 (dotted line). If the light is reflectedonto the diaphragm element 41, the corresponding color pixel remainsdark in the represented image. Instead of the tilting mirror matrices38, 39 and 40, reflective LCD modules may be used as well.

[0044] In a further embodiment of the invention, the projection optics11 of the additional-image generating module 7 are provided such that anintermediate image of the modulated image is generated in such a mannerthat the projection lens 3 may be used both for projection of thepositive film and for projection using the additional-image generatingmodule 7.

[0045] As the light modulator 10, a GLV module 42 may also be employed.FIGS. 6 and 7 schematically show the operation of such GLV module 42 (aswitchable diffracting reflection grating), which may be employed, forexample, in the light modulator shown in FIGS. 4 and 5 instead of thetilting mirror matrices 38, 39, 40 used therein. The GLV module 42comprises several parallel reflecting strips 43 for each image pixelwhich are alternatingly fixed in their position and positioned moveablein height. In a first adjustable position, all of said strips 43 aresituated in one plane, so that the light incident on the strips 43 via adeflecting element 44 is reflected back (FIG. 6). In a second positionof the strips 43, shown in FIG. 7, every other strip 43 is offset inheight relative to the other strips 43 so that the strips 43 form areflecting diffraction grating. Due to said diffraction, a large part ofthe incident light is not reflected back again to the deflecting mirror44. Thus, the intensity of the light reflected back by the deflectingmirror 44 is substantially lower than in the position of FIG. 6. Thisallows to realize brightness/darkness control of the image pixel. Thus,it is essential for this GLV module 42 that the angle of the lightreflected by this module be modifiable as described above and that,depending on said angle, the reflected light be used either to generatea bright image pixel or be directed to a beam trap and thus darkened. Itdepends essentially on the construction of the light modulator whetherthe reflected light (FIG. 6) or the diffracted light (FIG. 7) is usedfor a brightened image pixel. The GLV module 42 may be present as amatrix arrangement so that the image pixels are arranged in lines andcolumns. Alternatively, the GLV module 42 may be realized as a lineararrangement of image points. In this case, scanning of the image line orimage column is then required for imaging. This may be realized by knownscanning devices arranged following the light modulator 10.

[0046] In a further embodiment, the first partially reflective mirror 8may be provided such that the degree of splitting between the first andsecond partial beams varies over a beam cross-section of the lightincident on the first partially reflective mirror 8. Thus, there may be,for example, a variation over the image height of the positive image tobe projected, such that the positive image is illuminated as brightly aspossible, while in the region of the subtitles mainly theadditional-image generating module7 is illuminated.

[0047] The first partially reflective mirror 8 shown in FIG. 1 may alsobe attached to a carriage (not shown), which is displaceableperpendicular to the light propagation direction of the light ray bundle4 by means of a motor and a worm gear. This allows the first partiallyreflective mirror 8 to be moved into and out of the optical path. It isadvantageous to provide mechanically self-locking locking devices, bywhich the first partially reflective mirror 8 is locked, respectively,in the extended or in the retracted state. Thus, the drive system of thecarriage can be deenergized when the first partially reflective mirror 8is in the retracted or extended state. To this end, the locking devicesmay further be provided with limit switches, which emit a signal whenthe first partially reflective mirror 8 is in the desired retracted orextended state. In a further embodiment, a deflecting element (e.g. amirror) may be additionally provided, which is also attached to thecarriage and arranged following the first partially reflective mirror 8in the retracting or extending direction. In this case, the carriage canbe displaced in three different positions. In the first position, thefirst partially reflective mirror 8 is in the optical path (simultaneousprojection of the illuminated positive image and of the generatedadditional image), in the second position, only the deflecting elementis in the optical path, in order to direct the light onto the lightmodulator (only the image generated by the light modulator isprojected), and in the third position, neither the first partiallyreflective mirror 8 nor the deflecting element are in the optical path(only the illuminated positive image is projected).

1. A projection arrangement for projecting an image onto a projectionsurface (34), said arrangement comprising a light source (26), a filmstage (2), arranged following the light source, for holding a positiveimage recorded on a carrier medium, and projection optics (3) forprojecting a illuminated positive image, characterized by a control unit(25), a light modulator (10), which is controllable by said control unitin order to generate an additional image on the basis of predeterminedimage data, an optical device (11), arranged following said lightmodulator, for projecting said additional image onto the projectionsurface (34), and by a beam splitter (6), arranged between the lightsource (26) and the film stage (2), for splitting the light from thelight source (26) into a first partial beam directed to the film stage(2) in order to illuminate the positive image and into a second partialbeam which may be directed to the light modulator (10).
 2. Theprojection arrangement as claimed in claim 1, characterized in that thebeam splitter (6) is formed such that the degree of splitting betweenthe first and second partial beams varies over a beam cross-section ofthe light incident on the beam splitter (6).
 3. The projectionarrangement as claimed in claim 1 or 2, characterized in that the beamsplitter (6) comprises a partially reflective mirror (8), a beamsplitter block, or a deflecting element which is arranged partially in abeam cross-section of the light.
 4. The projection arrangement asclaimed in any one of claims 1 to 3, characterized in that the beamsplitter (6) is movable into and out of the optical path between thelight source (26) and the film stage (2).
 5. The projection arrangementas claimed in claim 4, characterized in that a deflecting device isfurther provided which, when the beam splitter (6) is moved out of theoptical path between the light source (26) and the film stage (2), ismovable into said optical path so as to direct the light from the lightsource (26) onto the light modulator (10).
 6. The projection arrangementas claimed in any one of claims 1 to 5, characterized in that the beamsplitter (6), the light modulator (10) and the optical device (11) arecomprised in one attachable projection unit.
 7. The projectionarrangement as claimed in any one of claims 1 to 6, characterized inthat a splitting device (13, 14, 15; 35, 36, 37) is provided, whichsplits the light from the light source (26) into different colorcomponents, and that the light modulator (10) comprises severallight-modulating units (21, 22, 23; 38, 39, 40), each of which modulatesone of said color components.
 8. The projection arrangement as claimedin claim 7, characterized in that a combining device (18, 19; 35, 36,37) is provided which combines the light emitted by the light-modulatingunits (21, 22, 23; 38, 39, 40) to form one single light bundle (20) andguides said light bundle to the optical device (11).
 9. The projectionarrangement as claimed in any one of claims 1 to 8, characterized inthat the light modulator (10) comprises an LCD module (21, 22, 23), atilting mirror matrix (38, 39, 40) or a GLV module (42).
 10. Theprojection arrangement as claimed in any one of claims 1 to 9,characterized in that the projection optics (3) and the optical device(11) are realized as one single projection unit.
 11. The projectionarrangement as claimed in any one of claims 1 to 10, characterized inthat a memory (30) for storing data and/or an input interface (27) forreceiving data as well as an output interface are provided.
 12. Theprojection arrangement as claimed in claim 11, characterized in that asound unit (28, 29) is provided which can extract sound data from saiddata and feed them into a sound system (33) via the output interface.13. The projection arrangement as claimed in any one of claims 1 to 12,characterized in that a display device (31) and an image recordingdevice are provided, said image recording device being able to recordthe image projected onto the projection surface (34) and to represent iton the display device (31).
 14. The projection arrangement as claimed inany one of claims 1 to 13, characterized in that the projectionarrangement is adapted to project moving images.
 15. A projection unitfor coupling to a projector, which projector comprises a light source(26), a film stage (2), arranged following said light source, forholding a positive image recorded on a carrier medium, as well asprojection optics (3) for projecting a illuminated positive image onto aprojection surface (34), said projection unit comprising a control unit(25), a light modulator (10) controllable by said control unit in orderto generate an additional image on the basis of predetermined imagedata, an optical device (11), arranged following the light modulator(10), for projecting the additional image onto the projection surface(34), and a beam splitter (6), wherein the beam splitter (6), when theprojection unit is coupled to the projector, is arranged between thelight source (26) and the film stage (2) and splits the light from thelight source (26) into a first partial beam directed to the film stagein order to illuminate the positive image and into a second partial beamwhich may be directed to the light modulator (10).